1. Field of the Invention
This invention relates generally to heat transfer mechanisms and more particularly to an improved heat transfer mechanism for removing the heat generated in and electronic circuit module assembly.
2. Prior Art
The efficient extraction of heat from electronic circuit modules for very large scale integrated circuit packages has presented a very significant limitation on the design capability and use of such electronic modules. Lacking an efficient heat transfer mechanism, the speed and power capabilities of the electronic circuit modules are severely limited. This becomes even more significant when a single electronic circuit module may contain a plurality of integrated circuit chips and related circuitry.
Early semiconductor devices solved the problem by making one of the electrodes of a single circuit device both a thermal and electrical direct contact to the external world with the electrode being connected to an efficient heat transfer device, such as a studded heat sink. This was especially convenient when the electrode could be maintained at, for example, ground potential. Typical discrete semiconductive devices of such a configuration are found in U.S. Pat. Nos. 3,719,862 and 3,836,825. This approach was also used in some of the early approaches to the removal of heat from integrated circuit packages. For example, in an article entitled "Conduction Cooled Heat Plate for Modular Circuit Package" in Volume 13, No. 2 of the July 1970 issue of the IBM Technical Disclosure Bulletin, there is disclosed a cooling technique using a conduction cooled, isothermal heat plate which is metallurgically connected via an appropriate slug to the various circuit chips in an integrated circuit package. With this technique, the chip is fixed at the potential of the heat plate.
With early devices such as high powered metal rectifiers, it was found necessary to also pass cooling air over the external portions of the electronic components. For example, U.S. Pat. No. 2,169,109 is directed to a parallel air flow delivery system for component cooling where the air flow is over and past the components, but is not a direct or redirected impingement jet and does not contain a backboard assembly. U.S. Pat. 2,380,026 is similar to the above-mentioned patent with the addition of a distributor manifold to selectively distribute the air. U.S. Pat. No. 2,843,806 discloses a parallel air flow feed design with each component being cooled by a pass-by air flow, rather than impingement.
U.S. Pat. No. 3,843,910 uses a cooling system which includes an air moving device and air cooled in a heat exchanger under the influence of an external fan which opens into a multiplicity of secondary pipes or circuits, each terminating in a calibrated passage, which allows a predetermined flow rate of fluid to pass. The cool fluid acts directly upon a component or indirectly upon a group of components by way of a fluid distribution box or plenum chamber. However, such a system does not necessarily provide a large degree of turbulence in the area of the object to be cooled and, in addition, is relatively complex in its configuration and the use of a heat exchanger for air cooling.